It is intuitive to judge the safety of drinking water principally on an observed absence of contamination.

This was the case at the birth of modern drinking water quality management: in 1855 John Snow (the founder of modern epidemiology) hesitated to link a substantial cholera outbreak to the Broad Street pump due to a lack of visible contamination in the water. To an extent this is also true in modern times, with water utilities typically offering insights into the microbial safety of drinking water based on an observed absence of specific pathogenic and indicator organisms. The context of water treatment and the ‘multiple-barrier’ approach is not necessarily (or usually) included in this discourse. Thus, an erroneous inference of operational response being made solely on the basis of lagging indicators may be made. Such a circumstance is not of benefit to the consumer or the utility.

Focussing consumer confidence reporting on critical control processes increases the importance of what is reported. Events known to be related to public health outcome are highlighted, and conversely, results not as strongly associated with public health outcome do not need to be included. Both cases are beneficial. Essentially, the connection between public health theory and drinking water supply practise can be reaffirmed. The introduction of a health-based target for the microbial safety of drinking water provides an opportunity to pursue such a shift in focus.